Knife sharpener



Aug.10,1948. f F w, DAVIS 2,446,909

KNIFE SHARPENER Filed Aug. 24, 1945 2 sheets-sheet 1 #41; r4 n f jzywzir Aug. 10, 1948. F. w. DAVIS KNIFE SHARPENER Filed Aug. 24, 1945 2 Sheets-Sheet 2 away: J 10 L/ 4 f f f Patented Aug. 10, 1948 {UNITED STATES ATEN T OFFICE KNIFE SHARPENER .Francis .W..Davis, Belmont, Mass.

Application. August-24, 1945, Serial -No.. 612,321

fi-Claims. 1

This :invention relates to knife sharpeners of that typeawhich employ hardened partly overlapping beveled disks between which the edge of the knifezto be sharpened iszdrawn.

'QDGQOfthB ODjBOES'Of thisinvention is to provide means {by :which the disks .may be turned readily from timetortime topresent fresh cutting edges :into effective :position.

Another object of :the invention is to provide apair of-sharpening-edges forgthe knife in which the -disksare differently spaced, thus to facilitate,a rough sharpening action :to onetaper, and a finish sharpening action to a different taper, and -;to;facilitate the removal ofany edge fin or feather-on the knifebeingsharpened and occasioned .by the=first or rough sharpening opera tion.

:A further object of the invention is to provide a fixed, support with which .the sharpener maybe-quickly engagedor disengaged, so that it may be used either whilesupported in the hand, 011i1'l a;rigidlyafixed position.

vStill another gobject is to ;provide a readily detachable guide;by which .a, scissors .blade .may

be; supported in sharpening'position-With respect to one of the. sharpening disks.

Further ,zobjects and advantages will appear from. a. completenescription of an embodiment of the invention shownin -theaccompanying drawings in which Figures 1 and 2 are-topedge and front elevations, respectively, of a-sharpener constructed in accordance with this invention.

FigureB isa detail sectional view to a larger scale on'line 3-3 of Figure 2.

Figure 4 is asomewhat diagrammatic view to a larger;scale,;and showing :the knifeedge portion in section, of cooperating portions of the left hand andcenter disk as shown in'FigureZ.

Figure 5 isa view-similarztorFigure 4,'but show ing the center and right hand disks.

Figure 6 is a detail sectional View .on line 6f5.of Figure 5.

Figure 7 is a detail sectional view through the edge portion of a knife blade sharpened as-shown in ,Figure "5.

:Figure Bis-a view similar; to Figure 4,zbut showingin'full linesva blade in-the condition of Figure 7, and indotted-linesthe corrective effectof the Qfinal finish: sharpening by :the left hand and center I disks.

.Figureswi) and ;10-are-front. and top plan views, respective1y,:of a rigid. supportfor the sharpener.

Figures Hand :12 are-leftand righthand elevations, respectively, ofrthe same.

'2 :Figure -13 is a perspective view'of .aisciss ors blade support.

Figure 14 is a view similar to aportionofiFigure 9,but showingthe support of Figure 13.in.operative position.

Figure 15 .is a detail sectional view .on 'line t 5I5'-of Figure 14.

:Figure 16 is a somewhat diagrammatic View illustrating the relations between the scissors blade supporta scissors-blade insharpening, position, and a sharpening disk.

.Figure 17 is a fragmentary theparts shown inFigure 16.

Referring to the drawings, at I is indicateda support of any suitable description, but herein shown aspprovided with ahandle 2 at one end. The, supporting portion ofthe support I isjormed asa fiat;plate,-the-,end. opposite to the handlegz being. suitably. supported during use against any convenient fixed element such-as atableonupright member of any suitable description.

.Journaledton the support I are threeperipherperspective .view of ally beveled disks cooperating with each otherin twopairs, one-pair comprising disks 3 andA and the other comprising the disks-4 and 5, .the disk 4 being commonto the two pairs.

Asbest showninFigure 3, each of thegdisks is journaled on a headed pivot member Ii which ,passes'throughthe support I and may have suitable means for securing it on the backface otthe support as by the nut 'I threaded onto its rear end. :Each of the disks has'bearing against i-ts forwardface a -knurledknob I0. .This knoblmay beprovided with one or more rearwardly directed projections such as the pins II which engage in perforations 1-2 in the corresponding disk ;and serve to connect the two together for angular adjustment about the pivot member-8. The .head l5 of eachpivotmember may be set into arecessifi in'theouter-end of the knob Illand beneath-the head-I5 and-in the base of the recess I 5 may-be positioned-a spring shown asaBelleville-washer I-"I. This acts to yieldingly tighten the -knob, disk, and support together for frictional turning of the-knob and disk. Thus each disk may be. turned by grasping .its knurled knob and .turning it to present a fresh cutting edge of the disk into activeposition with respect .to the:knife to.be sharpened.

:It will be noted that'the spacing between .the axes of the center disk 4 andthe end disks .3 and 5 is different, as shown the distance between the-axes of-the disks-3 and A being less than between :the axes of the disks 4 and 5. This causesthe active portions-of the disks ..3. and 4 to be somewhat higher from the central longitudinal axis of the support I which passes through the centers of the pivot members than the active portions of the disks 4 and 5, and the angles at which the cylindrical projections of the disk peripheries intersect is flatter between the disks 3 and 4 than between the disks 4 and 5 as shown by comparison of Figure 4, which shows the portions of the disks 3 and 4, and Figure 5 which shows portions of the disks 4 and 5. If now the support be held against a fixed member and a knife be drawn thereacross with its edge presented between the disks 4 and 5 in the direction shown by the arrow in Figure 6, the larger diameter edges of the beveled disks scrape away portions from opposite sides of the knife blade adjacent to its edge as shown at 20, this tending to reduce the knife edge to the general contour shown in Figure 5, except that the later engagement of the side of the knife edge against the periphery of the disk 4 tends to deflect the extreme edge of the blade laterally as shown in Figure 7.

If now the knife be given a light finishing sharpening movement between the disks 3 and 4, as shown in Figure 8, this feather may be removed or straightened and the extreme point of the edge reduced to a somewhat flatter angle following the contours imparted thereto by reason of the closer spacing of the disks 3 and 4 than of the disks 4 and 6. Thus a final finishing out of more obtuse angle than the first or roughing cut is produced on the knife edge and any feather occasioned by the preliminary or rough sharpening may be eliminated. The finishing stroke of the knife should be done under light pressure, as otherwise a feather edge might be thrown in the opposite direction by reason of the action of the disk 4 occurring after the action of the edge of the disk 3.

It will also be noted from an inspection of Figure 2 that the support I is prolonged downwardly below the apex of the peripheries of the cooperating disks so as to prevent the knife from being drawn between the disks at this side of the support where drawing of the knife in the same direction of the arrow of Figure 6 between the disks would not act to sharpen the knife as the knife edge would be presented first to the back faces of the cutting disk edges. The upper edge of the support is shown as notched at 25 between the disks 4 and 5 so as to permit the knife edge to pass fully into sharpening relation.

In some cases it may be desired to support the sharpener rigidly instead of holding it in the hand. I Where this is desired, it may be engaged in a supporting bracket such as is shown in Figures 9 to 12. This bracket comprises a strip 30 having upturned end portions 3| and 32. The intermediate portion 33 of the bracket may be secured to any fixed member such as a wall or table 34 as by screws 35. One upstanding end portion, such as 3|, is provided with a closed slot 36 therein of sufficient size to receive therein the free end 31 of the support to which the handle 2 is secured. The other end portion 32 is provided with an open top slot 39 within which the intermediate portion of the support and handle 2 may be thrust so that the handle and support take the position shown in dotted lines in Figures 9 and 10. In order to insure that the sharpener is assembled in the support right side up so that the disks are presented in sharpening position, one side portion 38 at one side of the slot 39 may be bent inwardly as shown best in Figures 9 and 10. Should it be attempted to insert the sharpener upside down in the bracket, this end 38 would strike against the sharpening disk 3 and prevent the placing of the sharpener in the bracket.

It will be noted that the end portions 3| and 32 are inclined slightly toward each other, this causing these parts to exert a frictional drag on the end disks 3 and 5, the end portions 3| and 32 springing apart slightly when the sharpener is being inserted in the bracket, so that the sharpener is held frictionally, but can be removed when desired by pulling upwardly on the handle 2 and then moving the sharpener lengthwise to disengage its end portion from the slot 36.

The bracket may also be provided with means for supporting a guide for a scissors blade by which this blade may be presented to one of the sharpening disks in sharpening position. Such a guide is shown detached in Figure 13 at 40. As shown it comprises a lower portion slit to form a pair of spring feet 4|, the upper portion of the guide being bent out of the plane of the feet 4| to form a guide face 42 against which the scissors blade 44 may be presented. The feet 4| are engaged with the intermediate portion 33 of the bracket and to facilitate this, this intermediate portion may be upwardly bowed at 43, where it is provided with a transverse slot 45. This slot is of suflicient length to permit the feet 4| to be sprung toward each other slightly and then inserted therein and released, whereupon the spring engagement of the feet 4| with the slot ends holds the guide 40 in proper position. The space between the feet 4| also provides room for the overlapping edge portions of the sharpening disks 4 and 5 to extend, as shown in Figure 1'7. The portion 40 provides a flat support for a scissors blade 44 with its face 46 adjacent to the cutting edge 41 in engagement with the cutting edge of the disk 5. With the blade 50 supported, it is only necessary to pull it across the cutting edge-of the disk as shown by the arrow in Figure 17 to sharpen the blade.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art that various changes and modifications might be made without departing from the spirit or scope of the invention.

I claim:

1. A knife sharpener comprising a support, a pair of peripherally beveled hard sharpening disks, a headed pivot member securing each of said disks to said support in overlapping relation and with beveled peripheries facing in the same direction, a knurled knob also journaled on each pivot member and operatively engaging the adjacent disk, and a spring positioned between each pivot head and the adjacent knob and holding the adjacent disk and knob for frictional turning on said pivot.

2. The combination with a sharpener having a handled support and a plurality of overlapping sharpener disks carried by said handled support, of a bracket for securement in fixed position and provided with arms to frictionally engage the end disks of said sharpener, one of said arms having a closed slot for receiving therein the outer end portion of said handled support and the other of said arms having an open ended slot into which an intermediate portion of said handled support may be pressed when said outer end portion has been inserted into said closed slot.

3. The combination with a sharpener having a handled support and a plurality of overlapping sharpener disks carried by said handled support, of a bracket for securement in fixed position and provided with arms to frictionally engage the end disks of said sharpener, one of said arms having a closed slot for receiving therein the outer end portion of said handled support and the other of said arms having an open ended slot into which an intermediate portion of said handled support may be pressed when said outer end portion has been inserted into said closed slot, a portion of said other arm at one side of said slot being defiected toward the other of said arms to prevent the engagement of said sharpener in incorrect position in said bracket by interference between said deflected portion and one of said disks.

4, The combination with a sharpener having a handled support and a plurality of overlapping sharpener disks carried by said handled support. of a bracket for securement in fixed position and provided with arms to frictionally engage the end disks of said sharpener, one of said arms having a closed slot for receiving therein the outer end portion. of said handled support and the other of said arms having an open ended slot into which an intermediate portion of said handled support may be pressed when said outer end portion has been inserted into said closed slot, and a guide for a scissors blade carried by said support, said guide presenting a face portion against which said blade may be engaged in position to present the cutting edge of said blade in sharpening relation to one of said disks.

5. The combination with a sharpener having a handled support and a plurality of overlapping sharpener disks carried by said handled support, of a bracket for securement in fixed position and provided with arms to frictionally engage the end disks of said sharpener, one of said arms having a closed slot for receiving therein the outer end portion of said handled support and the other of said arms having an open ended slot into which an intermediate portion of said handled support be pressed when said outer end portion has been inserted into said closed slot, and a guide for a scissors blade carried by said support, said guide presenting a face portion against which said blade may be engaged in position to present the cutting edge of said blade in sharpening relation to one of said disks, said guide and bracket having portions coacting to releasably support said guide in operative position.

6. The combination with a sharpener having a handled support and a plurality of overlapping sharpener disks carried by said handled support, of a bracket for securement in fixed position and provided with arms to frictionally engage the end disks of said sharpener, one of said arms having a closed slot for receiving therein the outer end portion of said handled support and the other of said arms having an open ended slot into which an intermediate portion of said handled support may be pressed when said outer end portion has been inserted into said closed slot, and a guide for a scissors blade, said guide presenting a face portion against which said blade may be engaged in position to present the cutting edge of said blade in sharpening relation to one of said disks, said guide having spaced resilient feet and said bracket having a slot into which said feet may be sprung for releasably securing said guide in 0perative position on said bracket.

FRANCIS W. DAVIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 543,552 Hayes July 30, 1895 563,023 Dearborn June 30, 1896 1,215,591 Tobin Feb. 13, 1917 1,516,997 Watts Nov. 25, 1924 1,743,359 Kulp Jan. 14:, 1930 FOREIGN PATENTS Number Country Date 126,256 Switzerland June 1, 1928 378,536 Italy Feb. 14, 1940 

